The invention relates to an ink cup used as an inking and wiping device on pad transfer printing machines, and more specifically to a generic ink cup.
An ink cup 1 for an internal centering pin holddown machine is shown in FIG. 1. The internal centering pin holddown machine affixes the cup to the machine by a spring plunger that enters a recessed hole 6 at the top of the cup 1 and bottoms at the base of the hole. Pressure applied by the spring plunger, or air cylinder, presses the ink cup 1 against the printing plate and helps wipe the printing plate clean. Additionally, the ink cup may contain additional recessed holes 7, 8 for placing magnets 4, 5 such that additional pressure is applied. These magnets 4, 5 are permanently attached to the ink cup 1, typically by glue. This type of ink cup typically has a one-piece cup body 9 and usually has a two-sided, easily removable doctoring ring 2.
An ink cup 20 for an external holddown machine is shown in FIG. 2. An external holddown machine, part of which is shown in part 22, affixes the cup 20 to the machine by applying downward pressure on an outside flange 25 located on the outside circumference of the ink cup. These cups generally have no magnets as they do not need assistance for downward pressure, and have a one piece cup body, with the flange 25 being integral to the cup 20. The doctoring ring 23 is generally one sided and either is difficult to remove or cannot be removed without destroying the cup 20. An ink plug 21 allows for filling the cup with ink without removing the ink cup 20 from the printing plate, and also allows one to vent the cup 20 in case of pressure build up within the cup 20.
The ink cup designs for both the external and internal holddown machines are not adaptable and do not permit much flexibility in how the ink cups may be used. For example, if a printing operation has various types of external holddown machines that require the outside flanges to be different shapes, size or height, completely different ink cups would be required by each machine, even though they may be the same size and may be used to print the same image. Similarly, if a printing operation has various type of internal centering pin machines that require different centering pin diameters or lengths, completely different ink cups would be required by each machine, even though they may be the same size and may be used to print the same image.
Machine owners need spare ink cups on hand in the event that an ink cup is damaged and also to speed ink changeover. If a print job requires that a logo change color from green to blue, the best and fastest way to make that changeover is to have a filled, spare ink cup ready to be put in the machine. Otherwise, the ink cup must be removed and completely cleaned, which is very time consuming, before being filled with the new color and put back in to the machine. Therefore, the printing operation typically is required to stock multiple ink cups for each type of holddown machines in use, adding to the total number of ink cups required. This places a burden on supply and maintenance, adding additional costs.
In accordance with one embodiment of the invention, a universal ink cup for a pad printing machine is presented. The ink cup includes a first cup having walls defining a reservoir for holding liquid, and an engageable coupling, removably coupled to the first cup, for affixing the ink cup to the pad printing machine.
In related embodiments of the invention, the engageable coupling includes a second cup. The first cup may include walls defining a hole such that the engageable coupling can be inserted in the hole and affixed to the first cup. The first cup and/or the engageable coupling may have threads for affixing the first cup to the engageable coupling.
In other related embodiments, the engageable coupling includes various walls for serving a variety of purposes. The walls may define a centering pin receptor such that a centering pin of the pad printing machine can be inserted into the centering pin receptor, so as to affix the universal ink cup to the pad printing machine. In other embodiments, the walls define a cavity such that a magnet can be inserted into the cavity. The magnet applies a magnetic force so as to press the ink cup against a printing plate. The walls may also define a cavity for inserting a spanner wrench, or a cavity for inserting an antirotation pin.
In still other related embodiments, an external flange is coupled to the first cup. Pressure may be applied to the external flange to accommodate ink cup mounting, or in other embodiments, the external flange may be utilized to simply affix the pad printing machine to the universal ink cup. The external flange may be removably coupled to the first cup. The universal ink cup may include means for bolting or screwing the external flange to the first cup, or the external flange may include threads for affixing the external flange to the first cup. Additionally, the first cup may include a support shoulder such that an exterior hold-down flange can be dropped onto the shoulder.
In other related embodiments, a doctoring ring is coupled to the first cup. The doctoring ring may be removably coupled to the first cup and may have two working edges. The universal ink cup may also include an ink plug removably coupled to the first cup.
In yet more related embodiments, the first cup, engageable coupling, or doctoring ring may be formed of material selected from the group of materials consisting of ceramics, metals, alloys, and polymers. The first cup may have an outer perimeter with a diameter range between 30 and 250 mm, and may have an outer perimeter defining a shape selected from the group of shapes consisting of a circle, oval, and polygon.
In another embodiment of the invention, a universal ink cup for a pad printing machine is presented that includes a first cup having walls defining a reservoir for holding liquid, and an external flange removably coupled to the first cup. Pressure may be applied to the flange to accommodate ink cup mounting, or in other various embodiments, the external flange may be utilized to simply affix the pad printing machine to the universal ink cup. In related embodiments of the invention, the first cup includes a support shoulder such that the flange is affixed to the first cup by dropping the flange onto the shoulder. The external flange may include threads for engaging the first cup. The universal ink cup may include means for bolting or screwing the external flange to the first cup.
In other related embodiments of the invention, the universal ink cup includes a doctoring ring coupled to the first cup. The doctoring ring may be removably coupled to the first cup, and may have two working edges.
In still other related embodiments of the invention, the universal ink cup may include an ink plug removably coupled to the first cup for performing at least one operation from the group of operations consisting of adding ink to the first cup and venting the first cup. The first cup and/or doctoring ring may be formed of material selected from the group of materials consisting of ceramics, metals, alloys, and polymers. The first cup may have an outer perimeter defining a circle with diameter range between 30 and 250 mm, and may have an outer perimeter defining a shape selected from the group of shapes consisting of a circle, oval, and polygon.
In another related embodiment of the invention, the universal ink cup may include an engageable coupling coupled to the first cup, for affixing the universal ink cup to a pad printing machine. The engageable coupling may include a second cup, and/or may be removably coupled to the first cup.
The engageable coupling may include various types of walls for serving a variety of purposes. The walls may define a cavity such that a centering pin of the pad printing machine can be inserted into the cavity so as to affix the universal ink cup to the pad printing machine. Alternatively, the walls may define a cavity for inserting a magnet, the magnet for applying a magnetic force so as to press the ink cup against a printing plate.
In accordance with another embodiment of the invention, a method for applying a liquid to a depression in a plate is presented. The method includes providing a cup having walls defining a reservoir for holding liquid and providing a first engageable coupling removably coupled to the cup. The cup is affixed to a first pad printing machine via the first engageable coupling. The plate is contacted with the cup, wherein pressure supplied by the first pad printing machine seals the cup against the plate.
In related embodiments of the invention, the cup is moved across the plate. The cup may be integrated with a solvent feeding system, or a liquid viscosity maintenance system.
In another related embodiment of the invention, the method further includes detaching the cup from the first pad printing machine. The first engageable coupling is removed from the cup. A second engageable coupling removably coupled to the cup is provided. The cup is affixed to a second pad printing machine via the second engageable coupling The plate is contacted with the cup, wherein pressure supplied by the second pad printing machine seals the cup against the plate.
In accordance with yet another embodiment of the invention, a method for applying a liquid to a depression in a plate includes providing a cup having walls defining a reservoir for holding liquid and providing a first external flange removably coupled to the first cup, the first external flange being non-magnetic. The cup is affixed to a first pad printing machine via the first external flange. The plate is contacted with the cup.
In related embodiments of the invention, the cup is moved across the plate. The cup may be integrated with a solvent feeding system, or a liquid viscosity maintenance system.
In another related embodiment of the invention, the method further includes detaching the cup from the first pad printing machine and removing the first external flange from the cup. A second external flange removably coupled to the cup is provided, the second external flange being non-magnetic. The cup is affixed to a second pad printing machine via the second external flange. The plate is contacted with the cup.